This study proposed a Y-type mixer which was driven by electroosmotic flow (Ex = 5 - 25 kV/m) with 7 different mixing angles (30¢X, 60¢X, 90¢X, 120¢X, -120¢X, -90¢X, -60¢X) to enhance mixing efficiency . The mixing performance of the device was demonstrated by using micro laser-induced fluorescence (£gLIF) technology to quantify the concentration distribution in the microchannel. Also, micro particle image velocimetry (£gPIV) was used for velocity measurements and analysis. It was found that the negative mixing angle could induce larger dead zone area than the positive one. The joule heating effect was found when electric field strength was larger than 15 kV/m. The combined dead zone and joule heating effect could enhance the mixing performance slightly. Although it has only a marginal effect on the mixing length for the positive mixing angles. Negative mixing angles allow a reduction of mixer size, which means a more efficient use of material and space. Finally, the best mixing angle was found to be -60¢X.

L’expérience Double Chooz étudie les anti-neutrinos électroniques provenant de réacteurs nucléaires pour mesurer le paramètre de mélange θ13 dans le phénomène d’oscillation des neutrinos. Deux détecteurs souterrains identiques sont placés à différentes distances des réacteurs de la centrale de Chooz dans les Ardennes. Le Détecteur Lointain est entré en service en avril 2011, et le Détecteur Proche en janvier 2015. Cette thèse présente une analyse des phases simple et double détecteurs de l’expérience. Les neutrinos sont détectés par désintégration β inverse dans Double Chooz, où un positron et un neutron sont émis, créant deux signaux coïncidents. Différentes analyses ont été menées sur des échantillons dans lesquels le neutron capture sur un atome de gadolinium ou d’hydrogène. Une analyse jointe des deux captures est également présentée. Les bruits de fond proviennent de la radioactivité ambiante et des muons atmosphériques (émetteurs (β-n), neutrons rapides et muons s’arrêtant et se désintégrant dans le détecteur). Cette thèse se focalise sur le développement de techniques pour réduire le bruit de fond lié aux muons se désintégrant dans le détecteur. Avec l’aide de collègues de l’APC et du MIT, un TPC à neutrons a été installé dans les deux laboratoires souterrains à Chooz. Cette chambre à projection temporelle, appelée DCTPC, remplie d’un mélange hélium/CF4 mesure le flux, le spectre en énergie, et la direction des neutrons rapides dans les deux laboratoires avec des blindages différents (respectivement 150 et 300 mètres équivalents d’eau pour le Laboratoire Proche et Lointain) / Double Chooz is a reactor anti-neutrino experiment which measures the θ13 mixing parameter in the neutrino oscillation phenomenon thanks to two identical underground detectors located at different distances from the two reactors of the Chooz nuclear power plant in the French Ardennes. The Far Detector started data taking in April 2011 and the Near Detector began operations in January 2015. This thesis presents an analysis of both the single- and twodetector phases. Neutrinos interact in Double Chooz through inverse β decay on protons, where positron and a neutron are emitted, creating two coincident signals. Analyses were performed for each detector on independent samples using the neutron capture on Gadolinium or on Hydrogen. A combined analysis, using both neutron captures is also presented. Backgrounds to the neutrino sample originate from the ambient radioactivity and the abundance of atmospheric muons (cosmogenic (β-n) emitters, fast neutron showers, and muons stopping and decaying inside the detector). This thesis focuses on developing techniques for measuring and reducing the Stopping Muon background. With colleagues from APC and MIT, a 60 litre neutron TPC was installed in both underground laboratories at Chooz. This low pressure He/CF4-based time projection chamber, called DCTPC, measures the flux, energy spectrum and direction of fast neutrons in both locations, with different overburdens (150 and 300 meters water equivalent for the Near and Far Laboratories respectively)

The Qweak experiment at Thomas Jefferson National Accelerator Facility (Jefferson Lab) will measure the proton's weak charge by measuring the parity violating asymmetry in elastic electron-proton scattering at very low momentum transfer, with the aim of determining the proton's weak charge with 4% combined statistical and systematic errors. The experimental apparatus includes a longitudinally polarized electron beam, a liquid hydrogen target, a room temperature toroidal magnetic spectrometer, and a set of precision detectors for the scattered electrons. The toroidal magnetic spectrometer, which will deflect away the inelastic scattered electrons and focus the elastic scattered electrons onto the detectors, plays a crucially important role in the experiment. In this thesis, in order to meet the requirements for the installation and calibration of the toroidal magnetic spectrometer, the numerical simulation of the spectrometer's magnetic field based on a realistic magnet model is discussed, a precise 3D field mapping is introduced, and some simulation results are provided. The zero-crossing analysis technique, which can be used to precisely infer the individual coil locations of the toroidal magnet, is presented and explored in detail. / October 2007

The Qweak experiment at Thomas Jefferson National Accelerator Facility (Jefferson Lab) will measure the proton's weak charge by measuring the parity violating asymmetry in elastic electron-proton scattering at very low momentum transfer, with the aim of determining the proton's weak charge with 4% combined statistical and systematic errors. The experimental apparatus includes a longitudinally polarized electron beam, a liquid hydrogen target, a room temperature toroidal magnetic spectrometer, and a set of precision detectors for the scattered electrons. The toroidal magnetic spectrometer, which will deflect away the inelastic scattered electrons and focus the elastic scattered electrons onto the detectors, plays a crucially important role in the experiment. In this thesis, in order to meet the requirements for the installation and calibration of the toroidal magnetic spectrometer, the numerical simulation of the spectrometer's magnetic field based on a realistic magnet model is discussed, a precise 3D field mapping is introduced, and some simulation results are provided. The zero-crossing analysis technique, which can be used to precisely infer the individual coil locations of the toroidal magnet, is presented and explored in detail.

The Qweak experiment at Thomas Jefferson National Accelerator Facility (Jefferson Lab) will measure the proton's weak charge by measuring the parity violating asymmetry in elastic electron-proton scattering at very low momentum transfer, with the aim of determining the proton's weak charge with 4% combined statistical and systematic errors. The experimental apparatus includes a longitudinally polarized electron beam, a liquid hydrogen target, a room temperature toroidal magnetic spectrometer, and a set of precision detectors for the scattered electrons. The toroidal magnetic spectrometer, which will deflect away the inelastic scattered electrons and focus the elastic scattered electrons onto the detectors, plays a crucially important role in the experiment. In this thesis, in order to meet the requirements for the installation and calibration of the toroidal magnetic spectrometer, the numerical simulation of the spectrometer's magnetic field based on a realistic magnet model is discussed, a precise 3D field mapping is introduced, and some simulation results are provided. The zero-crossing analysis technique, which can be used to precisely infer the individual coil locations of the toroidal magnet, is presented and explored in detail.

Neutral current Drell-Yan production in proton-proton collisions at the LHC was studied with the ATLAS detector. The 20.1 inverse femtobarn data set used in this precision measurement was collected in 2012 during which the LHC collided protons at a centre-of-mass energy of 8 TeV. The production rate or differential cross-section was measured in three-dimensions: invariant mass, absolute rapidity, and cosine of the polar angle in the Collins-Soper frame. A measurement of the forward-backward asymmetry was obtained from the differential cross-section by summing over the forward and the backward events and taking their difference. The three-dimensional differential cross-section measurement presented in this dissertation can be used to constrain the invariant mass- and rapidity-dependent parton distribution functions of the proton and the forward-backward asymmetry results can be used to extract a measurement of the weak mixing angle. / Graduate

The Qweak experiment has taken data to make a 2.5 percent measurement of parity violating elastic ep asymmetry in the four momentum transfer region of 0.0250 (GeV/c)2. This asymmetry is proportional to the weak charge of the proton, which is related to the weak mixing angle, sin2(thetaW). The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z° pole to test the Standard Model prediction. A description of the experimental apparatus is provided in this dissertation. The experiment was carried out using a longitudinally polarized electron beam of up to 180 microampere on a 34.5 cm long unpolarized liquid hydrogen target. The Qweak target is not only the world’s highest cryogenic target ever built for a parity experiment but also is the least noisy target. This dissertation provides a detailed description of this target and presents a thorough analysis of the target performance. Statistical analysis of Run 1 data, collected between Feb - May 2011, is done to extract a blinded parity violating asymmetry of size--299.7 +/- 13.4 (stat.) +/- 17.2 (syst.) +/- 68 (blinding) parts-per-billion. This resulted in a preliminary proton’s weak charge of value 0.0865 +/- 0.0085, a 9% measurement. Based on this blinded asymmetry, the weak mixing angle was determined to be sin2(thetaW) = 0.23429 +/- 0.00211.

Un vaste programme international est en cours pour déterminer les paramètres du phénomène d'oscillation des neutrinos et approfondir la connaissance de la matrice de mélange des neutrinos (MNSP). Le détecteur OPERA, qui est installé dans le laboratoire souterrain du Gran Sasso en Italie, a pour but principal de mettre en évidence l'apparition de neutrinos de type tau dans un faisceau de neutrinos initialement de type muon, produit au CERN (CNGS) 730 km en amont. Il est aussi en mesure de détecter les oscillations des neutrinos muon en neutrinos électron, donnant accès au paramètre de mélange sin(2θ13)2, où θ13 est le dernier angle de la matrice MNSP finalement déterminé en 2012 conjointement par Daya Bay, RENO et Double Chooz. Pour déterminer la présence des ντ dans le faisceau, le détecteur OPERA est composé de cibles calorimétriques utilisant une alternance de plaques de plomb et de films d'émulsion. Ceux-ci permettront de reconstruire les traces des particules chargées résultant des interactions neutrino avec une précision inégalable (de l'ordre du micron). La recherche des événements de signal d'oscillation νµ → νe sera basée sur l'aptitude à identifier les électrons, à rejeter les événements de fond où un π0 est produit et à soustraire le fond dominant intrinsèque provenant du faisceau. Ce travail de thèse a pour objectif l'élaboration de méthodes d'analyse pour améliorer les performances du détecteur OPERA dans la recherche d'oscillations νµ → νe . / An international program is ongoing to measure the neutrino oscillation phenomenon and to determine the neutrino mixing matrix (MNSP) parameters. OPERA is a long-baseline neutrino experiment located at the Gran Sasso Laboratory in Italy, 730~km from CERN, downstream in the CNGS neutrino beam. The OPERA experiment is designed and optimised for a direct appearance search of νµ → ντ oscillations. It can also detect the νµ → νe oscillation driven by sin(2θ13)2 , where θ13 is the last mixing angle finally measured by the Daya Bay, RENO, and Double Chooz experiments in 2012. To observe the presence of ντ interactions in the beam, the OPERA detector is composed of calorimetric targets made of a modular structure called the "brick": a sandwich of lead plates interspaced with emulsion layers. The latter allows reconstructing tracks of charged particles produced in the neutrino interactions with a micrometric resolution. The search for the νµ → νe oscillation signal is based on the capability of identifying the electrons, rejecting background events where neutral pions are produced and keeping under control the intrinsic and dominant background source from the beam contamination. This work aims to elaborate analysis methods to improve the OPERA detector performance in the νµ → νe oscillation search.

Orientador: Marcelo Moraes Guzzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-21T20:53:09Z (GMT). No. of bitstreams: 1 Zavanin_EduardoMarcio_M.pdf: 2031044 bytes, checksum: a24fad776402ee2c06c0d5c44baaf4bb (MD5) Previous issue date: 2013 / Resumo: O objetivo desse trabalho é desenvolver um mecanismo que possa servir como solução para as anomalias dos antineutrinos de reatores e do Gálio. Relaxando a hipótese de Pontecorvo, permitindo que os ângulos de mistura que compõem um estado de sabor possuam diferentes valores, conseguimos explicar o fenômeno de desaparecimento de neutrinos/antineutrinos em baixas distâncias, através de um parâmetro livre. Para confrontar o mecanismo desenvolvido também fazemos uma analise criteriosa de alguns limites experimentais obtidos por aceleradores de partículas e identificamos uma possível dependência desse parâmetro livre com a energia. Adotando esse dependência energética para o parâmetro livre, conseguimos acomodar a grande maioria dos dados experimentais em física de neutrinos através de um único modelo / Abstract: This project aims the development of a mechanism that provides a possible solution to reactor antineutrino anomaly and Gallium anomaly. Relaxing the Pontecorvo\'s hypothesis, allowing the mixing angles that compose a flavor state possesses different values, it is possible to explain the phenomenon of desappearance in short-baselines, through a free parameter. To confront the mechanism developed we also perform an analysis of some experimental limits obtained by particle accelerators and identify a possible dependence of this free parameter with the energy. Adopting this energetic dependence for the free parameter, we can¿t almost every experiment in neutrino physics through a single model / Mestrado / Física / Mestre em Física

L’expérience Double Chooz a pour but la mesure précise de l’angle de mélange θ₁₃. Son évaluation repose sur l’étude de la disparition des antineutrinos produits par les réacteurs de la centrale de Chooz, disparition due au phénomène d’oscillation des neutrinos. Deux détecteurs identiques composés de liquide scintillant permettent d’effectuer une mesure relative, diminuant ainsi les incertitudes systématiques. Le détecteur proche, qui fournit la normalisation du flux de neutrinos émis, est en cours d’installation, son achèvement est prévu pour le printemps 2014. Le détecteur lointain, sensible à l’effet de θ₁₃, est situé à un kilomètre environ et prend des données depuis 2011. Dans cette première phase de l’expérience, les données acquises par le détecteur lointain sont comparées à une prédiction du flux de neutrinos émis par les réacteurs pour estimer le paramètre θ₁₃. Au sein de cette thèse, l’expérience Double Chooz et son analyse sont présentées. Une attention particulière est portée à l’étude des bruits de fond et au rejet de signaux parasites constitués de flashs lumineux émis par les photo-multiplicateurs. Les flux de neutrons aux interfaces entre les différents volumes du détecteur affectent la définition du volume d’interaction et partant l’efficacité de détection. L’étude détaillée de ces effets de bord est présentée. Dans le cadre de l’expérience Double Chooz, des études ont été menées afin d’améliorer la prédiction des flux de neutrinos émis par les réacteurs. Ces travaux ont mis à jour un déficit des taux de neutrinos observés dans les expériences passées à courtes distances des réacteurs. Ce déficit pourrait s’expliquer par une oscillation vers une saveur stérile. Le projet Stereo a pour but d’observer la distorsion — caractéristique de l’oscillation — du spectre des neutrinos en énergie et en distance de propagation. Cette thèse s’attache à présenter le concept du détecteur, les simulations réalisées, ainsi que les études de sensibilité. Les différents bruits de fond et les blindages envisagés pour s’en prémunir sont enfin discutés. / The Double Chooz experiment aims to measure the θ₁₃ mixing angle through the disappearance—induced by the oscillation phenomenon—of anti-neutrinos produced by the Chooz nuclear reactors. In order to reduce systematic uncertainties, the experiment relies on the relative comparison of detected signals in two identical liquid scintillator detectors. The near one, giving the normalization of the emitted flux, is currently being built and will be delivered in spring 2014. The far detector, sensitive to θ₁₃, is located at about one kilometer and is taking data since 2011. In this first phase of the experiment, the far detector data are compared to a prediction of the emitted neutrino flux to estimate θ₁₃. In this thesis, the Double Chooz experiment and its analysis are presented, especially the background studies and the rejection of parasitic signals due to light emitted by photo-multipliers. Neutron fluxes between the different detector volumes impact the definition of the fiducial volume of neutrino interactions and the efficiency of detection. Detailed studies of these effects are presented. As part of the Double Chooz experiment, studies were performed to improve the prediction of neutrino flux emitted by reactors. This work revealed a deficit of observed neutrino rates in the short baseline experiments of last decades. This deficit could be explained by an oscillation to a sterile state. The Stereo project aims to observe a typical signature of oscillations: the distortion of neutrino spectra both in energy and baseline. This thesis presents the detector concept and simulations as well as sensitivity studies. Background sources and the foreseen shielding are also discussed.